RE: Activation groups for beginners -- RPG400-L

Buck,

Just to expand a bit on source conversion from OPM to ILE....  I typically
think of RPGIII when someone says "OPM", so a necessary "first step" is
getting the code reformatted as an RPGIV member.  The goal on the initial
conversion is maximum compatibility with the OPM program.  Once the source
has been reliably migrated to the new format, then ILE can be incorporated
into the programs as needed.

A couple of gotchas that the newcomer should be aware of. I don't expect
this list is complete, just some of the most common.  These are from my
personal experience, so feel free to chime in if I missed something
important.  Thanks......

1) Numeric truncation - Like it or not, some programmers have come to depend
on the old truncation rules.  Those date conversion algorithms (MULT
10000.0001) and the like would not function correctly without the old rules,
and RPGIV issues an error (by default) when it happens.  For maximum
compatibility, use control spec TRUNCNBR(*YES) to restore the old rules for
the initial conversion. Note that this will NOT affect truncation rules for
expressions.

2) Numeric calcs to expressions - Some conversion tools will try to convert
numeric algorithms to expressions.  Looks pretty, but differences in the way
expressions and "fixed format" operators behave makes this a risky
modification.  NOTE: IBM does not add this feature in its CVTRPGSRC utility.

3) IGNDECERR - This compile option for RPGIII is not available for RPGIV.
However, RPGIV has FIXNBR(*{NO}ZONED *{NO}INPUTPACKED) which is probably
similar enough

4) Use Control specs to define the environment - Programs converted from
RPGIII to RPGIV should include control specs to better define the
environment and compiler options.  Use DFTACTGRP(*YES) for all newly
converted members. Once the program begins to use ILE features, the control
specs change.


Eric DeLong
Sally Beauty Company
MIS-Sr. Programmer/Analyst
940-898-7863 or ext. 1863



-----Original Message-----
From: Buck Calabro [mailto:Buck.Calabro@commsoft.net]
Sent: Tuesday, March 05, 2002 4:58 PM
To: rpg400-l@midrange.com
Subject: RE: Activation groups for beginners


>What I was getting at is that if you put all
>of your programs in QILE, and then scope
>the overrides to the default *ACTGRPDFN,
>the override will affect any other programs
>running in the QILE actgrp.
>
>This is different than DFTACTGRP(*YES) because
>in that situation it goes by call-level, and
>when that call level ends, so does the override.
>
>This is why I think *NEW/*CALLER is easier for
>new people to understand.

I can't outright disagree; I just picked a scenario that I see a lot of and
figured I'd work off of that.

In a mixed OPM/ILE environment where I'm converting one program at a time, I
can't guarantee that the program calling my new ILE *CALLER code isn't OPM.

  --buck
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